“Educating people about just how real this disorder is and how it's not just being tired is crucial.” – Scott

The Role of Histamine in Sleep and Wakefulness

The hypothalamus contains multiple neuronal systems that help promote and stabilize wakefulness.1-3

In the CNS, histamine neurons originate only in the hypothalamic tuberomammillary nucleus (TMN) and project widely throughout the brain to activate neurons in the cortex, thalamus, and other regions outside of the hypothalamus containing wake-promoting neurons (e.g., norepinephrine, acetylcholine, serotonin neurons).2,4 In vivo and in vitro animal studies have shown that histamine neurons also inhibit non-REM sleep– and REM sleep–promoting neurons, helping to stabilize wakefulness during the day.2,4,5,6

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Watch to learn about the role of histamine in regulating sleep and wakefulness.1,2,4-6

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Thomas Scammell, MD from Beth Israel Deaconess Medical Center, Boston Children's Hospital, and Harvard Medical School, discusses key data from several animal studies that support why histamine plays an important role in disorders characterized by sleep-wake state instability, such as narcolepsy.1,4

Sudden and brief loss of muscle strength or tone, often triggered by strong emotions. Narcolepsy with cataplexy is known as type 1 narcolepsy.

Complete collapse to the ground; all skeletal muscles are involved.

Only certain muscle groups are involved.

Biological clock mechanism that regulates the 24-hour cycle in the physiological processes of living beings. It is controlled in part by the SCN in the hypothalamus and is affected by the daily light-dark cycle.

Frequent inappropriate transitions between states of sleep and wakefulness.

The inability to stay awake and alert during the day.

A neurotransmitter that supports wakefulness. The TMN is the only source of histamine in the brain.